Renewable energyRenewable energy is a source of energy that can never be exhausted.
We can obtain renewable energy from the sun (solar energy), from the water (hydropower), from the wind (windmills), from hot dry rocks, magma, hot water springs (geothermal) and even from firewood, animal manure, crop residues and waste (Biomass).

The random production of wind energy cannot easily be accommodated on the grid by switching on and off conventional energy suppliers, like coal fired power plants, which would lead to an increase of CO2 emissions, rather than the reduction of CO2 emissions which is desired.

In order to accommodate the random production of wind energy in the grid, it would be most convenient when alternative (renewable and conventional) electricity producers could balance out the difference between production of wind energy and electricity demand. The Night Wind project aims to store wind energy produced at night in refrigerated warehouses, and to release this energy during daytime peak hours.

Nature adds some more details about the first tests of the Night Wind idea.

Later this year, van der Sluis's team will start a demonstration project by setting up a wind turbine next to the Netherlands' largest coldstore, in Bergen op Zoom, a small town in the SouthWest of the country. It shouldn't be technically difficult, he says — it's really just a question of developing software to match the temperature of the warehouses with electricity demand, turning the fridge on and off as the supply from the wind plant and the demand from consumers change during the day.

This project will officially end in June 2008 and I hope it will be a success. In the mean time, you can read this short presentation of the project, from which the diagram above has been extracted (PDF format, 3 pages, 100 KB).

Sources: Declan Butler, Nature, February 7, 2007; and various other websites